One of the most popular topics today is the implementation of the “glycemic index” into our diets, which refers to the rise in glucose levels after a meal. Diets today such as nutrisystem base their entire diet on the “glycemic advantage” claiming that low GI carbs are good, while sugars, etc. are what causes fat gain.

Probably the only debate of whether or not we should have high GI carbs post workout has been this very issue – fat gain and decreased insulin sensitivity. Because there is no denying it is optimal for performance, glycogen replenishment, and protein balance.

Surprisingly, despite all of the hoopla over the miracle that is low GI carbs, I have failed to find substantial evidence supporting these claims.

Now before you glycemic index disciples flog me (!) please read on first! As I was once a disciple myself, but am now questioning my convictions. [img]/forum/images/graemlins/tongue.gif[/img]

“There is no evidence to support prescribing diets such as "no concentrated sweets" or "no sugar added." (E) “

“Meal plans such as no concentrated sweets, no sugar added, low sugar, and liberal diabetic diet also are no longer appropriate. These diets do not reflect current diabetes nutrition recommendations and unnecessarily restrict sucrose.”

“There is not sufficient, consistent information to conclude that low–glycemic load diets reduce the risk for diabetes. Nevertheless, low–glycemic index foods that are rich in fiber and other important nutrients are to be encouraged. (E) “

“There is debate as to the potential role of low–glycemic index and –glycemic load diets in prevention of type 2 diabetes. Although some studies have demonstrated an association between glycemic load and risk for diabetes, other studies have been unable to confirm this relationship, and a recent report showed no association of glycemic index/glycemic load with insulin sensitivity (39).

Thus, there is not sufficient, consistent information to conclude that low–glycemic load diets reduce risk for diabetes. Prospective randomized clinical trials will be necessary to resolve this issue. Nevertheless, low–glycemic index foods that are rich in fiber and other important nutrients are to be encouraged. A 2004 American Diabetes Association statement reviewed this issue in depth (40), and issues related to the role of glycemic index and glycemic load in diabetes management are addressed in more detail in the CARBOHYDRATE section of this document.”

Now lets discuss some of this research. Basically, most of the evidence in support of low GI foods are correlational studies in large cohorts. For example, McKeown et al. (2004) investigated the relationship between carbohydrate-related dietary factors, insulin resistance, and the prevalence of the metabolic syndrome in the Framingham Offspring Cohort (2,834 subjects), which is a longitudinal community-based study on cardiovascular disease using the offspring of participants of the Framingham Heart Study Cohort. Altogether, participants consuming high glycemic carbohydrates were 40% more likely to have metabolic syndrome than participants consuming low glycemic carbohydrates. For those of you that do not know, Metabolic Syndrome is a cluster of metabolic abnormalities that increases the risk of cardiovascular disease, diabetes, and other disorders. However, other correlation studies were not consistent with McKeown (see Lau et al., 2005)

There has been few type “A” studies on this subject. Intervention studies in animals has shown a strong correlation with high fructose and sucrose diets to insulin resistance (Storlien et al., 2000); however, these studies are either hypercaloric or contain unrealistic sugar contents (i.e. 70-80% of total calories).

Neil et al. (2006) performed one of the rare type A studies on the effects of carbohydrate composition on insulin resistance. They investigated the effects of two eucaloric, identical fiber content, low vs. high sucrose diets (25 vs. 10%, respectively, of total energy intake) in 13 healthy subjects aged 33 (± 3 years; BMI 26.6 ± 0.9 kg/m2), in a randomized crossover design with sequential 6-week dietary interventions separated by a 4-week washout. Results showed no differences between conditions in insulin sensitivity, glycemic profiles, or measures of vascular compliance. Suggesting that carbohydrate composition has little effect on insulin resistance syndrome when fiber and calories are controlled for.

What research does support is that:

1.) Low fiber diets
2.) Hypercaloric diets

Do increase insulin resistance.

When you control for these factors, the correlation between high GI foods and metabolic abnormalities disappears.

Now, I don’t think I can make extreme recommendations on this like consuming all of your carbs from sugar – research does NOT support this. But based on this, I think it is silly to fuss over 1 or 2 high GI carbohydrates centered around your workout routines to optimize performance. And really, I am not sure how much we should fuss over having moderate GI carbs, or even higher, as long as we have a lot of fiber in our diet (10 g per 1000 calories). But I can’t say for sure…

Here is a direct study that examined the effects of post workout sugar consumption on body comp and performance.

I’ve been hesitant to full on adopt the Glycemic Index as belief. From my earlier research into when I was cutting, it seemed that the GI was more based on the label of what foods contained and less upon how the body’s insulin levels were actually affected.

So I used it with a grain of salt and just targeted foods with more fiber and less sugars. I did however keep my maltodextrin &amp; dextrose in my PWO shake; I tried to keep [the [PWO shake] in the mornings though, for the insulin resistance properties already occurring at that time of day.

But I’m a reasonably healthy person. Once you start throwing diabetes, cardiovascular disease, and other issues… I think you are correct that there are many studies that have yet to be run before any conclusions arise.

Venom

01-11-2008 11:30 PM

Re: Sugar and other high GI Carbs - are they the Enemy?

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I did however keep my maltodextrin &amp; dextrose in my PWO shake; I tried to keep it in the mornings though for the insulin resistance properties already occurring at that time of day.

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What did you try to keep in the mornings? Not quite sure whether you meant dextrose / malto or low Gi fibrous carbs?

What do you think is the optimal breakfast and why? That is something I want to research a lot more!

amino

01-14-2008 07:33 PM

Re: Sugar and other high GI Carbs - are they the Enemy?

I meant that I tried to keep the PWO malto/dextrose consumption early in the morning. Sorry about the confusion. I’ll edit that.

As far as THE optimal breakfast… wouldn’t that depend on your goals and the other areas of your daily diet?

If the goal is bodybuilding (bulking and cutting), then I have become a believer that quick digesting protein along with complex carbohydrates is the answer. This is the guy that would have defined breakfast a year ago as Bacon, eggs, French toast, &amp; maple syrup.

But I cannot deny my successes so far with eating protein every meal combined with a complex carb or essential fat source. But limit the carbs &amp; fats being consumed together. Carbs in the 1st half of the day when insulin resistance is lowest. And fats in the evenings as metabolism slows and you prepare to minimize catabolic activity during sleep.

So now I eat my eggs at night for the fat. Steak and eggs before I go to bed. =) Midnight snack is the new breakfast, you know? Yum!

I had probably eaten oatmeal 100 time in my life prior to last year. Now I’ve eaten oats &amp; protein shake probably 300 of the past 365 mornings.

sucramdw

01-17-2008 03:56 AM

Re: Sugar and other high GI Carbs - are they the Enemy?

I have been talking with some of the professors at school because I started that Club on campus that we talked about. The sports nutrition researcher who is an RD as well told me that the glycemic index in itself has no validity. He said that the methodology is very different with different studies, and one food will have 1 range of glycemic index numbers with someone, while it will be completely different with another individual. So the glycemic index in itself is not accurate, when followed by the numbers for certain foods. After saying this, he said, "but I still follow it." I think, because there is research showing that by eating foods said to have a low glycemic index, the chances of diabetes does decrease.

I would love to know more about this however, because higher glycemic carbohydrates replenish glycogen so much faster, and it would seem like a high glycemic carb in the morning would make more sense if it didn't mess with your insulin sensitivity.

Venom

01-17-2008 04:52 AM

Re: Sugar and other high GI Carbs - are they the Enemy?

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After saying this, he said, "but I still follow it." I think, because there is research showing that by eating foods said to have a low glycemic index, the chances of diabetes does decrease.

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lol. But I have to somewhat agree w/ his sentiment.

The main point I think is that sugar, at least up to 20% of your diet based on the research, is not going to increase incidences of metabolic syndrome.

But low fiber diets and excess calories appear too.

Naturally, if you include fiber in your food, this will lower the GI. So I don't think you can have a completely high GI carbs, and have the amount of fiber you need to have. Hence, why I think generally having low / moderate GI foods is a good thing.

I think its especially a solid recommendation for the general pop, because they don't consume nearly enough vegetables as most bodybuilders do.

Based on this research, the main thing I would say is that I don't think we should fear having high GI carbs around our workout. And as long as we include adequate fiber, I don't think we should worry about moderate GI carbs, either. I.E. brown rice, popcorn (which rocks!), rice cakes...As long as you have your fiber. I have been adding broccoli for instance to most of my carb meals.

Right now, my carbs come from sugar around my workouts. Then I have rice, rice cakes, and popcorn. It's paradise. [img]/forum/images/graemlins/grin.gif[/img]